Plate Tectonics & Plate Boundaries – Vocabulary Flashcards

32 vocabulary flashcards summarizing essential terms and definitions from the lecture on plate tectonics, plate boundaries, and related geological processes.

Plate Tectonics Theory

Scientific concept that Earth’s lithosphere is divided into moving plates whose interactions shape the planet’s surface.

Plate Boundary

A location where two tectonic plates meet and interact.

Divergent Boundary

Constructive plate margin where plates move apart and new crust forms, often marked by mid-ocean ridges.

Convergent Boundary

Destructive plate margin where plates move toward each other, commonly creating subduction zones or mountain belts.

Transform Boundary

Conservative plate margin where plates slide horizontally past one another along faults.

Subduction Zone

Region at a convergent boundary where one plate sinks beneath another into the mantle.

Mid-Ocean Ridge

Elevated seafloor feature produced at divergent boundaries by upwelling magma and seafloor spreading.

Rift Valley

Linear depression formed on land at a divergent boundary where the crust is pulled apart.

Hydrothermal Vent (Black Smoker)

Seafloor hot-water spring found along mid-ocean ridges, expelling mineral-rich fluids.

Continental-Oceanic Convergence

Collision between continental and oceanic plates in which the denser oceanic plate subducts beneath the continent.

Oceanic-Oceanic Convergence

Meeting of two oceanic plates where one subducts, often generating island arcs.

Continental-Continental Convergence

Collision of two continental plates producing extensive folding, faulting, and high mountain ranges.

Island Arc

Curved chain of volcanic islands formed above a subducting oceanic plate.

Mountain Range

Linear group of mountains produced mainly at convergent plate boundaries (e.g., Himalayas).

Oceanic Trench

Deep, elongated depression on the ocean floor created by subduction of one plate beneath another.

Slab Pull Theory

Idea that gravity acting on a cold, dense subducting plate edge helps drive plate movement.

Convection (Mantle)

Heat-driven circulation of mantle material that transfers energy and moves tectonic plates.

Heat Loss Hypothesis

Proposal that Earth’s internal heat escaping via convection contributes to plate motion.

Gravity Hypothesis

Suggestion that gravitational forces acting on elevated ridges and subducting slabs help move plates.

Lithosphere

Rigid outer shell of Earth, comprising crust and uppermost mantle, broken into tectonic plates.

Asthenosphere

Ductile, partially molten upper mantle layer upon which lithospheric plates glide.

Constructive Boundary

Another term for a divergent boundary where new crust is generated.

Destructive Boundary

Alternative name for a convergent boundary where crust is consumed in subduction.

Conservative Boundary

Synonym for a transform boundary where crust is neither created nor destroyed.

Triple Junction

Point where three plate boundaries (ridge, trench, or transform) intersect.

Ridge-Ridge Transform Fault

Transform fault connecting two segments of a divergent ridge; plates move oppositely between ridge crests.

Ridge-Trench Transform Fault

Transform fault linking a spreading ridge to a subduction trench.

Trench-Trench Transform Fault

Transform fault that connects two subduction zones at separate convergent boundaries.

Pacific Plate

Largest tectonic plate, mostly oceanic, bordered by many active boundaries around the ‘Ring of Fire.’

Eurasian Plate

Major tectonic plate covering most of Europe and Asia.

Subduction-Generated Magma

Melted material produced when water-rich oceanic crust descends and lowers mantle melting point.

Seafloor Spreading

Process of new oceanic crust formation at mid-ocean ridges and its outward movement.